Propeller-pitchometer.



L. FRANK.

PROPELLER PITCHOMETER.

APPLICATION FILED OCT. 21. 1914.

Llfifififig Patented May 18, 1915.

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' To all whom it may concern This invention relates to measurin instruments, and more especially'to pitc ometers; and the object of the same is to produce a machine for measuring the pitch of the blades of propellers.

To thisend the invention consists in the details of. construction hereinafter more fully :described'and claimed, and as shown in the drawings wherein' Figure 1 is a plan view of one form of this instrument mounted upon a propeller (the latter being shown in dotted lines), ready for use excepting that the arms of the pitchometer are turned'a little to one side from a-position truly overlying two of the blades or flakes of the propeller; and F g. 2 is a left side elevation of Fig. 1 with the instrument lurned so that its arms truly coincide with two of the propeller blades. F ig. 3 is a central vertical section through the instrument alone, taken on the line 33 of Fig.1.} Fig. 4 is a plan view of another forn'i Ofthe gage plate comprising but a single arm, and Fig. 5 is a sectional detall on thexlinet ii of Fig. 4. Fig; 6 is a perspective viewsof another form of the instrument comprising but a single arm which itself is adjustably supported 'on the hub member Broadly speaking, the instrument comprises a hub member, a plate made in one or w i Thetwo arms,"and aseries of set screws. hub-member :cpmprises a centering pin. 1 which is adapted to fit closely into the bore in the-hubof the propeller indicated at P, a

lower block 2 preferablyrectangular in contour and integral with'the upper end of the piiil', the upper e'xtreniity'of the block being beveled ras atfi an upper block 4: also prefer-- ably rectangularfin contour and of thesame size asthe lower block andwith its lower extremitybeveled as at 5, a bolt 6 which extendscentrally through holes in the two ,blocks and throughout the length of the pin 1 andhas its head 7 disposed at the lower PROPELLER-PITGHOMETER.

Specification of Letters Patent.

Patented May is, 1915.

Application filed October 21, 1914. serial No. 867,582.

end of the latter, a jam-nut 8 on the upper threaded end of the bolt 6, and a guideplate having one leaf 9 lying along the longer side of the lower block 2 and' the shorter side of the upper block 4, a head leaf 1O overlying the fiat upper end of the upper block 4 and pierced with a hole through which the bolt 6 projects, and a lip 11 hanging over the longer face of the upper block tall as best seen in Figs. 2 and 3. Ordinarily the propeller will be laid upon a suitable support, such as a pair of horses not shown, and. the pin 1 passes "down through the bore of its hub whereby the hub member above described, and the parts carried by it, will be supported above the propeller and may be rotated from time to time.

The head 7 of the boltlfi will therefore be smaller than the hole in the propeller hub and smaller than the pin 1 so that it may pass through said hole; and, while I prefer to make the blocks 2 and 4 square in contour, they may be of any other appropriate shape." The leaf 9 overlying corresponding faces of the two blocks causes them to approach each other in such manner when the thumb-nut is turned that their beveled faces 3 and 5 remain ever in parallelism, and therefore any fiat member which is placed between these faces will be clamped thereby when the thumb-nut 8 is set up sufi'iciently.

The second member of this instrument is a plate of proper metal and of sufficient thickness to make it quite rigid. In the first three views of the drawings this plate is shown as having two arms 15 and 16 which are of corresponding and similar construction and are connected integrally by an interposed shank 17 pierced with a hole 18 through which the bolt 6 may pass, and in the other views the plate is composed of but a single arm which corresponds with one of the two arms infthe double-armed construction, and need not therefore be elaborately described. .When the double-armed plate is used, its arms will lie approximately or exactly in a single plane which is the plane of the shank l7, and the latterwillbe clamped between the beveled faces 3 and 5 of thehub needs some means to support it by the hub member. In F 1,2. fl it is projected at one edge into a shank 19 which has the-hole 18 for the passage of the bolt 6, the same as in the two-armed plate;

changed and it maybe used on a propeller blade inclined in the opposite direction.

The'ineans for supporting the single arm shown inFig. 6 is described below.

Through each arm are boredholes 20 which Stand on lines strictly at right angles to the plane of the arm, and through each hole is passed a "set screw 21, preferably having a ilattened head 22 possibly provided with a number to match the same number stamped on the llillZC adjacent the hole 20. ()nto the body 0 the set screw runs a nut 23 which, mayfit with considerable friction thereon or may be held thereon against rotation by a jam nut 21, and the lower or working end of the set screw is preferably reduced as shown at 25. There will be as many holes and set screws as de-' sired, and they are widely scattered throughout the area covered bythe arm, although I consider it essential that a row of'the holes shall be disposedaround the edge of this" arm in any event, and quite a number near its center for purposes yet to appear.

In the form of my invention illustrated in Fig. 6, the hub member has the same pin 30,

. a single block 31 provided with a series of transverse holes 32 different elevations and in different directions, and no guide-plate or jam screw. The plate has a single arm 33 pierced with holes 20 for the set screws 21. The'con'nections between the block and arm, however, are different. Herein the shank is in p a bolt 34 passing through one of the holes 32 and held by a nut 35 on-each side of the block 31, and the outer end of the bolt passes under a clip 36 secured upon the arm in any suitable way as by rivets 37, and is held in said 'clip by a set screw 38. The body of this bolt 34 is round, and where it passes under the clip the latter is rounded. The

'result is that when the set screw isvloosened the clip, and withit the entire arm and the set screws carried by such arm, may be rocked over the outer end of the bolt 3% to adjust the plane of the plate with reference to the axial line of the pin 30; after which the set screw 38 can be set up tight to hold the plate or arm in such adjustment. this extent from those illustrated-in theother views, because it can be. used on the blades of proellers whose pitch or angles vary, and can E: aeeommoilated to such varying pitch by means of the 'set screw 38.

The use of this device is as follows: The propeller l" is laid on a suitable support, and the pin 1 or ill) is passed through the hole in the hub. .ll it be a right-hand propeller, the proper arm of the plate shown in l igs.

as to give him access to the face of .peller blade from timeto time he swings this arm back passing through it at.

its hub nen'iber the form of To this form of my invention differs have to be trued by suitable machining. In" order to ascertain when the grinding off of said rough material 18 suliicient, this testing a left-hand prodevice or pitchometer'is brought into place. 5

As the workman treats each blade or fluke of the propeller, the arin of the instrument is turned aside' as indicated partly by the dotted position of the propellerin Fig. 1, so

upon which he is working; and

the prov into position directly above the propeller blade so that the tips 25 of the set screws contact therewith. 'Bythis means he can readily ascertain which set screw contacts first, and thereby he is informel what part of the face of the propeller blade treated or ground off to a greater until all of the tips 25 contact simultaneously. If it is the, intention'to give the propeller blade agreater pitch, the set' screws will be adjusted accordingly by means of their set nuts 23 and 24. "If the propeller be one which is to rotate in the opposite direction, hewill use st'rument shown in Figs. 1, 2and 3, or he may. remove the plate shown in Fig, 4 from and reverse it, passing the hole 18 over the bolt Gland clamping it between the beveled faces of the two bloeksas before, and withdrawing the set screws 21 through the holes 24' from the opposite direction until their nuts- 23 contact with the then upper face'of the The si ngle-arm type of blade shown;

and inserting them arm. in Fig. (i obviously may not bethus reversed because the clip but the especial function of this form of my inventionfis to provide a single whose blades'have a variety of pitches or inclinations, whereas the adj ustability of the several set screws in any form of my instrui'nent is obviously for the purpose for must be, extent and theother arm of the in or bracket 36 will interfere,

instrument which may be'used on different propellers varying the pitch or inclination at'di/tlferent' any propeller-lilade. a pitchonieter for propoints on the face of Thus is produced pellers by described may jeasily be carried 'outL Also the instrument is useful for centering the screws so as to secure true adjustmentof the propeller on its shaft. The instrument is further useful For old propellers where it is supposed that they have been strained or ipute pos-,

injured, and in some cases it is sible to use the instrument for taking the means of which the objectsabove.

; pitch of existing propeller blades so asto add a new one which may have, become broken off or injured beyond repair. The size and proportion of parts, as well as their material and the exact details of construction, are matters of no moment.

What is claimed asnew is:

1. The hereindescribed pitchometer for propeller blades, the same comprising a hub member having a pin adapted to enter the hole in the propeller hub, a plate having a series of threaded holes through it, screws through said holes with their tips adapted to contact with the face of the propeller blade, a shank connected with the plate, and adjustable connections between the shank and hub member whereby the position of the plate with respect to the blade may be changed.

2. The herein described pitchometer for propeller blades, the same comprising a hub member having a pin adapted to enter the hole in the propeller hub, a plate having a series of pendant elements adapted to contact with the face of the propeller blade, a support for the plate, and movable threaded connections between the support and hub member whereby the position of the plate with respect to said member is rendered adjustable.

3. In an instrument of the class described, the combination with a hub member comprising a lower block with a beveled upper face, a pin depending from said block, an upper block with a beveled lower face, and

meaiis for drawing said blocks toward each other; of a plate having a shank adapted to be clamped between said beveled faces and a series of holes through its body, and set screws through said holes, for the purpose set forth. I

4. In an instrument of the class described, the combination with a hub member consisting of a lower block having a beveled upper face and a tubular pin projecting from its lower face, an upper block having abeveled lower face and a hole through its body, a bo t extending through said hole and through the lower block and pin and having a reduced head at the lower end of said pin, and a jam nut on the upper end of said bolt; of a plate having a shank adapted to be clamped between said beveled faces and a series of holes through its body, and set screws through said holes, for the purpose set forth.

5. In an instrument of the class described, the combination with a 'hub member con-. 'sisting of a lower block having a beveled upper face and a tubular pin project1ng from its,lower face, an upper block having 1 a beveled lower face and a hole through its fromgthe"first-named face, and means for [drawing *said blockstoward each other; of

body, a bolt extending through sa d hole and through the lower block and pin and blade.

said pin, and a jam nut on the upper end of said bolt; of a plate conforming in conof adjustable elements on said plate adapt-' ed to contact with the face of the propeller- 6. In an instrument of the class described,

the combination with a hub member comprising a lower block of rectangular contour having its upper face beveled, a hole through its body, and a tubular pin depending rigidly from its lower face, an upper block of corresponding contour having a hole through its body and its lower face beveled, a guide plate having a leaf lying along one exterior face of both blocks, a second leaf overlying the upper block and pierced with a hole, and a lip depending alongside that face of the upper block which is remote from the first-named face, a bolt extending through the pin and both blocks and the upper leaf of the guide-plate, and a jam nut on the upper end of the bolt; of a plate having a shank pierced with a hole adapted to receive said bolt when the shank stands between the beveled faces of the blocks, and a series of adjustable pendant members on said plate adapted to contact with the upper face of the propeller blade, for the purpose set forth.

7. In an instrument of the class described, the combination with a hub member comprising a lower bloclr of rectangular contour having its upper face beveled and a pin depending rigidly from its lower face, an uper block of corresponding contour having its lower face beveled, a guide plate having a leaf lying along one exterior face of both blocks, a second leaf overlying the upper block, and a lip depending alongside that face of the upper block which is remote from the first-named face, and means for drawing said blocks toward each other; of a plate having a shank standing between the beveled faces of the blocks, and a series of adjustable pendant members on said plate adapted to contact with the upper face of the propeller blade, for the purpose set forth.

8. In an instrument of the class described, the combination with a hub member comprising a lower block of rectangular contour havingits upper face beveled and a pin de- 4 pending rigidly from its lower face, an uphavinga reduced head at the lower end of plate comprising two arms and an inter,-

posed shank all standing in a single plane 5 series of screws adapted to pass through the holes in eitherv arm from either direchon, and nuts on said screws. I

In testimony whereof I afiix my signature in presence of two witnesses,

LAWRENCE FRANK. Witnesses:

R0131. M. F ENKLIN, O. HARPER ANDERSON. 

